GB2235407A - Contact lens mould - Google Patents

Contact lens mould Download PDF

Info

Publication number
GB2235407A
GB2235407A GB9017839A GB9017839A GB2235407A GB 2235407 A GB2235407 A GB 2235407A GB 9017839 A GB9017839 A GB 9017839A GB 9017839 A GB9017839 A GB 9017839A GB 2235407 A GB2235407 A GB 2235407A
Authority
GB
United Kingdom
Prior art keywords
moulding
mould
tubular portion
mould part
female
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9017839A
Other versions
GB2235407B (en
GB9017839D0 (en
Inventor
Michael James Sealey
Michael James Kelly
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MJS Scientific Ltd
Original Assignee
MJS Scientific Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by MJS Scientific Ltd filed Critical MJS Scientific Ltd
Publication of GB9017839D0 publication Critical patent/GB9017839D0/en
Publication of GB2235407A publication Critical patent/GB2235407A/en
Application granted granted Critical
Publication of GB2235407B publication Critical patent/GB2235407B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/30—Mounting, exchanging or centering
    • B29C33/303—Mounting, exchanging or centering centering mould parts or halves, e.g. during mounting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C39/00—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor
    • B29C39/22—Component parts, details or accessories; Auxiliary operations
    • B29C39/26—Moulds or cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00009—Production of simple or compound lenses
    • B29D11/00038—Production of contact lenses
    • B29D11/00057—Production of contact lenses characterised by the shape or surface condition of the edge, e.g. flashless, burrless, smooth
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/00009—Production of simple or compound lenses
    • B29D11/0048—Moulds for lenses
    • B29D11/005—Moulds for lenses having means for aligning the front and back moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
    • B29C37/005—Compensating volume or shape change during moulding, in general
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/0002—Condition, form or state of moulded material or of the material to be shaped monomers or prepolymers

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ophthalmology & Optometry (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)

Abstract

A pair of cast plastics mould parts, for moulding an ophthalmic contact lens, comprising a female, mould part with upwardly facing concave surface and with a tubular portion extending upwardly from its periphery; and a male, mould part which has a downwardly facing convex surface at its lower end and is received within the tubular portion of the female mould, so that the convex and concave moulding surfaces are juxtaposed to define therebetween a moulding cavity and, around and above the moulding cavity, an annular reservoir for liquid moulding material; wherein the radially inner surface of the tubular portion of the female mould has three angularly spaced radially inwardly extending projections for abutment with the outer surface of the male mould; or the outer surface of the male mould has three angularly spaced radially outwardly extending projections for abutment with the inner surface of the tubular portion of the female mould; in either case for maintaining axial alignment between the two parts. <IMAGE>

Description

CONTACT LENS MOULD A technique, which has recently become popular for the manufacture of ophthalmic correction contact lenses from plastics material, is known as cast moulding. In this technique, two plastics male and female mould parts with respective convex and concave moulding surfaces are injection moulded from master dies and are subsequently juxtaposed to provide a moulding cavity between the convex and concave moulding surfaces. A polymerisable liquid moulding material is cast and polymerised within the moulding cavity to form a contact lens, whereafter the mould parts are separated to release the lens and are disposed of.
Conventionally each female mould part is positioned with its concave surface facing upwardly and a predetermined dose of polymerisable material is fed into the female mould part, after which the male mould part is caused to move downwardly so that an annular portion engages and seals against the female mould part to define the periphery of the moulding cavity with a predetermined volume of the polymerisable material trapped within the cavity. The two mould parts are then held together over a period of some hours, while the liquid moulding material polymerises. The integrity and shape of the moulding cavity, and hence of the moulded lens are critically dependent upon exact axial alignment between the two mould parts.If there is any tilting of one relatively to the other, one side of the lens will be too thick and the other side too thin, resulting in unacceptable, so called, lens prism.
In accordance with the present invention, a pair of cast plastics mould parts, for use in the moulding of an ophthalmic contact lens, comprises a first, female, mould part with a nominally upwardly facing concave moulding surface and with a tubular portion extending upwardly from a peripheral portion of the concave moulding surface; and a second, male, mould part which has a nominally downwardly facing convex moulding surface at its lower end and which is arranged to be received within the tubular portion of the first mould part, so that the convex and concave moulding surfaces are juxtaposed to define therebetween a moulding cavity and, around and above the moulding cavity, an annular reservoir for liquid moulding material; wherein the radially inner surface of the tubular portion of the first mould part has three angularly spaced radially inwardly extending projections for substantial abutment with the radially outer surface of the second mould part; or the radially outer surface of the second mould part has three angularly spaced radially outwardly extending projections for substantial abutment with the radially inner surface of the tubular portion of the first mould part; in either case for maintaining substantial axial alignment between the two mould parts.
By substantial abutment is meant touching or a clearance of up to 0.015mm, and preferably no more than O.Olmm.
With this arrangement, the essential annular reservoir between the two mould parts is maintained, for accommodating excess liquid moulding material when the two mould parts are juxtaposed, and for providing any liquid moulding material which needs to be drawn into the moulding cavity during polymerisation, to accommodate shrinkage, whilst the three projections provide automatic self alignment between the two mould parts, to avoid tilting and the production of undesirable lens prism.
The invention is illustrated diagrammatically in the accompanying drawings, in which: Figure 1 is an axial section; and, Figure 2 is a section taken on the line II-II in Figure 1.
The illustrated mould has female and male parts 3 and 4 which provide respective part spherical concave and convex moulding surfaces 5 and 6 defining therebetween a moulding cavity 7, when the parts are brought into abutment in coaxial alignment. The abutment occurs where an annular rib 9 on the part 4 engages and seals against the surface 5. The seal separates the moulding cavity 7 from an annular reservoir 8. It would be equally possible for the rib 9 to be formed at an edge of the concave surface 5.
Axial alignment between the mould parts 3 and 4 is assured either by three equiangularly spaced projections 10 on a cylindrical tubular portion 11 of the mould part 3, substantially engaging a cylindrical tubular portion 12 of the mould part 4; or by three equiangularly spaced projections 13 on the cylindrical portion 12 of the mould part 4 substantially engaging the cylindrical part 11 of the mould part 3.

Claims (2)

1. A pair of cast plastics mould parts, for use in the moulding of an ophthalmic contact lens, the pair comprising a first, female, mould part with a nominally upwardly facing concave moulding surface and with a tubular portion extending upwardly from a peripheral portion of the concave moulding surface; and a second, male, mould part which has a nominally downwardly facing convex moulding surface at its lower end and which is arranged to be received within the tubular portion of the first mould part, so that the convex and concave moulding surfaces are juxtaposed to define therebetween a moulding cavity and, around and above the moulding cavity, an annular reservoir for liquid moulding material; wherein the radially inner surface of the tubular portion of the first mould part has three angularly spaced radially inwardly extending projections for substantial abutment with the radially outer surface of the second mould part; or the radially outer surface of the second mould part has three angularly spaced radially outwardly extending projections for substantial abutment with the radially inner surface of the tubular portion of the first mould part; in either case for maintaining substantial axial alignment between the two mould parts.
2. A pair of cast plastics mould parts, for use in the moulding of an ophthalmic contact lens, substantially as described with reference to the accompanying drawings.
GB9017839A 1989-08-29 1990-08-14 Contact lens mould Expired - Fee Related GB2235407B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB898919532A GB8919532D0 (en) 1989-08-29 1989-08-29 Contact lens mould

Publications (3)

Publication Number Publication Date
GB9017839D0 GB9017839D0 (en) 1990-09-26
GB2235407A true GB2235407A (en) 1991-03-06
GB2235407B GB2235407B (en) 1993-01-13

Family

ID=10662221

Family Applications (2)

Application Number Title Priority Date Filing Date
GB898919532A Pending GB8919532D0 (en) 1989-08-29 1989-08-29 Contact lens mould
GB9017839A Expired - Fee Related GB2235407B (en) 1989-08-29 1990-08-14 Contact lens mould

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB898919532A Pending GB8919532D0 (en) 1989-08-29 1989-08-29 Contact lens mould

Country Status (1)

Country Link
GB (2) GB8919532D0 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996016780A2 (en) * 1994-11-29 1996-06-06 Allergan, Inc. Cast molding of intraocular lenses
WO2001042001A1 (en) * 1999-12-09 2001-06-14 Johnson & Johnson Vision Care, Inc. Molds for use in contact lens production
US8287269B2 (en) * 2005-12-12 2012-10-16 Johnson & Johnson Vision Care, Inc. Molds for use in contact lens production
US20130313404A1 (en) * 2012-05-25 2013-11-28 Cory R Katterhenry Reduced-tilt back plastic feature for a contact lens mold
US10133089B2 (en) 2015-05-13 2018-11-20 Bausch & Lomb Incorporated Cast molding toric contact lenses

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996016780A2 (en) * 1994-11-29 1996-06-06 Allergan, Inc. Cast molding of intraocular lenses
WO1996016780A3 (en) * 1994-11-29 1996-09-19 Allergan Inc Cast molding of intraocular lenses
US5620720A (en) * 1994-11-29 1997-04-15 Allergan Cast molding of intraocular lenses
WO2001042001A1 (en) * 1999-12-09 2001-06-14 Johnson & Johnson Vision Care, Inc. Molds for use in contact lens production
US8287269B2 (en) * 2005-12-12 2012-10-16 Johnson & Johnson Vision Care, Inc. Molds for use in contact lens production
US20130313404A1 (en) * 2012-05-25 2013-11-28 Cory R Katterhenry Reduced-tilt back plastic feature for a contact lens mold
US10133089B2 (en) 2015-05-13 2018-11-20 Bausch & Lomb Incorporated Cast molding toric contact lenses

Also Published As

Publication number Publication date
GB8919532D0 (en) 1989-10-11
GB2235407B (en) 1993-01-13
GB9017839D0 (en) 1990-09-26

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20010814